/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.EvaluatorException;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.JavaScriptException;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.ScriptableObject;
import org.mozilla.javascript.WrappedException;
/**
* The shell program.
*
* Can execute scripts interactively or in batch mode at the command line.
* An example of controlling the JavaScript engine.
*
* @author Norris Boyd
*/
public class Shell extends ScriptableObject
{
private static final long serialVersionUID = -5638074146250193112L;
@Override
public String getClassName()
{
return "global";
}
/**
* Main entry point.
*
* Process arguments as would a normal Java program. Also
* create a new Context and associate it with the current thread.
* Then set up the execution environment and begin to
* execute scripts.
*/
public static void main(String args[]) {
// Associate a new Context with this thread
Context cx = Context.enter();
try {
// Initialize the standard objects (Object, Function, etc.)
// This must be done before scripts can be executed.
Shell shell = new Shell();
cx.initStandardObjects(shell);
// Define some global functions particular to the shell. Note
// that these functions are not part of ECMA.
String[] names = { "print", "quit", "version", "load", "help" };
shell.defineFunctionProperties(names, Shell.class,
ScriptableObject.DONTENUM);
args = processOptions(cx, args);
// Set up "arguments" in the global scope to contain the command
// line arguments after the name of the script to execute
Object[] array;
if (args.length == 0) {
array = new Object[0];
} else {
int length = args.length - 1;
array = new Object[length];
System.arraycopy(args, 1, array, 0, length);
}
Scriptable argsObj = cx.newArray(shell, array);
shell.defineProperty("arguments", argsObj,
ScriptableObject.DONTENUM);
shell.processSource(cx, args.length == 0 ? null : args[0]);
} finally {
Context.exit();
}
}
/**
* Parse arguments.
*/
public static String[] processOptions(Context cx, String args[]) {
for (int i=0; i < args.length; i++) {
String arg = args[i];
if (!arg.startsWith("-")) {
String[] result = new String[args.length - i];
for (int j=i; j < args.length; j++)
result[j-i] = args[j];
return result;
}
if (arg.equals("-version")) {
if (++i == args.length)
usage(arg);
double d = Context.toNumber(args[i]);
if (d != d)
usage(arg);
cx.setLanguageVersion((int) d);
continue;
}
usage(arg);
}
return new String[0];
}
/**
* Print a usage message.
*/
private static void usage(String s) {
p("Didn't understand \"" + s + "\".");
p("Valid arguments are:");
p("-version 100|110|120|130|140|150|160|170");
System.exit(1);
}
/**
* Print a help message.
*
* This method is defined as a JavaScript function.
*/
public void help() {
p("");
p("Command Description");
p("======= ===========");
p("help() Display usage and help messages. ");
p("defineClass(className) Define an extension using the Java class");
p(" named with the string argument. ");
p(" Uses ScriptableObject.defineClass(). ");
p("load(['foo.js', ...]) Load JavaScript source files named by ");
p(" string arguments. ");
p("loadClass(className) Load a class named by a string argument.");
p(" The class must be a script compiled to a");
p(" class file. ");
p("print([expr ...]) Evaluate and print expressions. ");
p("quit() Quit the shell. ");
p("version([number]) Get or set the JavaScript version number.");
p("");
}
/**
* Print the string values of its arguments.
*
* This method is defined as a JavaScript function.
* Note that its arguments are of the "varargs" form, which
* allows it to handle an arbitrary number of arguments
* supplied to the JavaScript function.
*
*/
public static void print(Context cx, Scriptable thisObj,
Object[] args, Function funObj)
{
for (int i=0; i < args.length; i++) {
if (i > 0)
System.out.print(" ");
// Convert the arbitrary JavaScript value into a string form.
String s = Context.toString(args[i]);
System.out.print(s);
}
System.out.println();
}
/**
* Quit the shell.
*
* This only affects the interactive mode.
*
* This method is defined as a JavaScript function.
*/
public void quit()
{
quitting = true;
}
/**
* Get and set the language version.
*
* This method is defined as a JavaScript function.
*/
public static double version(Context cx, Scriptable thisObj,
Object[] args, Function funObj)
{
double result = cx.getLanguageVersion();
if (args.length > 0) {
double d = Context.toNumber(args[0]);
cx.setLanguageVersion((int) d);
}
return result;
}
/**
* Load and execute a set of JavaScript source files.
*
* This method is defined as a JavaScript function.
*
*/
public static void load(Context cx, Scriptable thisObj,
Object[] args, Function funObj)
{
Shell shell = (Shell)getTopLevelScope(thisObj);
for (int i = 0; i < args.length; i++) {
shell.processSource(cx, Context.toString(args[i]));
}
}
/**
* Evaluate JavaScript source.
*
* @param cx the current context
* @param filename the name of the file to compile, or null
* for interactive mode.
*/
private void processSource(Context cx, String filename)
{
if (filename == null) {
BufferedReader in = new BufferedReader
(new InputStreamReader(System.in));
String sourceName = "